FRONT AXLE AND REDUCTION DIFFERENTIAL

Description .................................................................................................................................. 6 - 1

Removal and Installation .......................................................................................................... 6 - 2

Front Wheels ........................................................................................................................ 6 - 2
Front Axle and Reduction Differential ................................................................................ 6 - 4

Disassembly and Reassembly .................................................................................................... 6 - 6

Front Axle ............................................................................................................................ 6 - 6
Reduction Differential .......................................................................................................... 6 - 11

Adjustment .................................................................................................................................. 6 - 21
Tooth Contact Patterns and Adjustment .............................................................................. 6 - 21 6
Troubleshooting .......................................................................................................................... 6 - 22

Service Data ................................................................................................................................ 6 - 23

 FRONT AXLE AND REDUCTION DIFFERENTIAL

Description
1.5 to 2.5 ton models
11

13
12 14

Nut

10 8
15 2 4 3 7 9 5 6
1
206452

3 to 3.5 ton models 11

13
12
14
Remarks:
Hub nut is identical
with those of
1.5 to 2.5 ton models

1 15 2 4 3 7 9 5 6 10 8
206453

1 Front wheel hub 6 Differential gear 11 Input flange

2 Frame support 7 Differential case 12 Drive gear
3 Axle shaft 8 Differential carrier 13 Driven gear
4 Axle housing 9 Reduction bevel gear 14 Carrier cover
5 Differential pinion 10 Reduction bevel pinion 15 Backing plate

The frame support is bolted to the front axle on it. The reduction differential is mounted on
housing, together with the backing plate of the axle housing. The input flange carries a
wheel brake. The hub carries a single wheel but, drive gear which is in mesh with the driven gear
with optional rim, double tires can be mounted mounted on the reduction bevel pinion.

6-1
FRONT AXLE AND REDUCTION DIFFERENTIAL

Removal and Installation

Front Wheels
[Single wheel] 2
Removal sequence 1
[Single wheel]
1 Wheel nuts
2 Front wheel
[Double wheels]
1 Extension valve
2 Outer wheel nuts [Double wheels]
3 Front wheel (outer) 5
4 Inner wheel nuts 4
5 Front wheel (inner)

3
1
2

200225

Suggestions

1. Block the rear wheels.

2. Pull the parking brake lever, and loosen the
wheel nuts 1 to 2 turns.
3. Raise the front end of the truck by jacking or
hoisting.
(1) Method using a hoist
Use two eye-bolts and slings as shown. And
lift the front end with a hoist.

204845

6-2
 FRONT AXLE AND REDUCTION DIFFERENTIAL

(2) Method using hydraulic system

Tilt the mast all the way backward. Put wood
blocks under the mast, and tilt the mast for-
ward to raise the front end.
CAUTION
After raising the front end, securely support it
by blocking properly.

200227

4. In case of the double wheels, remove the outer

wheel nuts and outer wheel. Then, remove the
Outer wheel nut
inner wheel nuts and the inner wheel.

Inner wheel nut

200228

Installation
1
To install, follow the reverse of removal sequence,
and do the following steps:
6 3
1. Tighten the wheel nuts to the specified torque
so that the wheels will not wobble during
operation.
4 5
1.0 to 1.8 ton 2 to 3.5 ton
models models
2 200229
157 N·m 378 N·m
Tightening torque
(16 kgf·m) (38.5 kgf·m)
for wheel nuts
[116 lbf·ft] [278 lbf·ft]

CAUTION Loosen outer Tighten inner Tighten outer

When retightening the wheel nuts for the dou- wheel nuts. wheel nuts. wheel nuts.
ble wheels, be careful not to forget tightening
the inner wheel nuts.

Double wheel nut tightening sequence

200230

6-3
FRONT AXLE AND REDUCTION DIFFERENTIAL

Front Axle and Reduction Differential

Removal

13 9 12 11 4

10
6

2
14
Oil level plug
Drain plug
8 7
3 1
207134

Sequence
1 Front wheel 8 Mast
2 Nuts 9 Brake pipe
3 Forks, Lift bracket 10 Parking brake cable
4 Return hose for lift cylinder 11 Universal joint
5 High-pressure hose for lift cylinder 12 Bolt, Nut
6 Tilt cylinder socket pin 13 Bolt, Nut
7 Mast support bearing cap 14 Front axle and Reduction differential

NOTE
1) For removal of front wheel 1, refer to
Removal, Front Wheels.
2) For removal of mast parts 2 thru 8, refer to
MAST AND FORKS.
3) Before removing the front axle and reduc-
tion differential, drain differential oil by
removing the front axle drain plug.

6-4
 FRONT AXLE AND REDUCTION DIFFERENTIAL

Suggestions
Bolt
1. Removing bolt 12
Bolt 12, right and left, are coupling the transmis-
sion with the differential. Before removing these
bolts, place a block under the transmission.

204847
2. Removing parking brake cable
To remove the parking brake cable, remove the
parking brake lever from the dashboard, and dis-
connect the cable from the lever.

NOTE
To dismount the differential only, remove the
front axle as explained above. To dismount
the engine & transmission assembly, remove
the differential with the front axle on the
frame.

Installation
To install, follow the reverse of removal sequence,
and do the following steps:
1. After installing the parking brake cable, make 245 to 294 N
sure that the brake lever operating effort is Parking brake lever
(25 to 30 kgf)
within the specifications. operating effort
[55 to 66 lbf]
2. Before installing the mast, bleed the brake
fluid circuits. For bleeding, refer to BRAKE
SYSTEM.
3. After installing the mast, make sure that the
tilt angles, forward and backward, are correct
and that the lift chains, right and left, are equal
in tension. Refer to MAST AND FORKS.
4. Fill the front axle housing with oil up to the 4.2 liters
Refill 1-ton models
plug hole. capacity of (1.1 U.S. gal)
front axle 2-ton models 5.0 liters
housing 3-ton models (1.3 U.S. gal)

6-5
FRONT AXLE AND REDUCTION DIFFERENTIAL

Disassembly and Reassembly

Front Axle
Disassembly

6
7

5
204848

Sequence
1 Axle shaft 4 Tapered roller bearing (outer), Oil seal,
2 Lock nut, Lock washer, Oil seal, Tapered Oil deflector
roller bearing (inner) 5 Tapered roller bearing (inner), Seal retain-
3 Hub & Drum assembly [Front wheel hub, er
Brake drum, Wheel bolts, Drum nuts, 6 Brake assembly
Tapered roller bearing (outer)] 7 Frame support, Axle housing

Start by:
1. Remove the mast. For replacement of the front
axle housing and disassembly of the differen-
tial, refer to MAST AND FORKS.
2. Jack up the truck. NOTE
3. Support the front end of the truck at both sides It is not necessary to remove the axle hous-
with blocks or stands to keep the truck in hor- ing nor to drain the oil for removing the axle
izontal position. shaft only.
4. Remove the front wheels.

6-6
 FRONT AXLE AND REDUCTION DIFFERENTIAL

Suggestions
1. Removing lock nut
Use a lock nut wrench (special tool).
Special tool needed
1.0 to 1.8 ton 2 to 3.5 ton
models models Special tool
Lock nut
91268-00800 03703-59001
wrench

204849

2. Removing front wheel hub

Use a wheel hub puller (special tool).
Special tool needed Special tool
1.0 to 1.8 ton 2 to 3.5 ton
models models
Wheel hub
64309-40100
puller (puller MH061017
(64309-10601)
seat)
204850

NOTE
It is not necessary to remove the oil seal from
the hub nor to disassemble the oil deflector
unless the seal is defective.

3. Removing bearings
The inner race of the tapered roller bearing
remains in the axle housing when the hub is drawn
out. Remove this race together with the seal
retainer with a bearing puller.

204851

6-7
FRONT AXLE AND REDUCTION DIFFERENTIAL

Inspection after disassembly

1. Axle shafts
(1) Looseness of mating splines
Mount the differential bevel gear on the
splined end of the shaft, and set a dial indica-
tor as shown. Rotate the bevel gear against the
contact point of the indicator and read the free
movement (looseness of mating splines).
A = Assembly standard
B = Repair or service limit Unit: mm (in.)
0.007 to 0.17 200235
Free movement A
(looseness of (0.0028 to 0.0067)
mating splines) B 0.5 (0.020)

(2) Runout
(a) Set a dial indicator at the middle part of Runout of shaft
the axle shaft. Rotate the shaft against the
contact point of the indicator and read the
runout of the shaft.
A = Assembly standard
B = Repair or service limit Unit: mm (in.)
1.0 to 1.8 ton 2 to 3.5 ton
models models Face runout of flange
0.5 (0.020) 1.0 (0.039) 200236
Runout of axle A
shaft (1/2 of dial maximum maximum
indicator reading) B 1.0 (0.039) 2.0 (0.079)

(b) Set a dial indicator against the flange of

the axle shaft as shown. Rotate the shaft
against the contact point and read the face
runout of the flange.
A = Assembly standard
B = Repair or service limit Unit: mm (in.)
Face runout of A 0.05 (0.0020)
axle shaft flange B 0.5 (0.020)

2. Axle housing
(1) Check the surfaces of axle housing in contact
with the mast bearing for damage.

(2) Check the entire axle housing for distortion,

dents and other defects, paying particular
attention to the welds to see if any weld is
cracked to require repair.

6-8
 FRONT AXLE AND REDUCTION DIFFERENTIAL

3. Others
(1) Check the outer surface of the oil seal retainer
for wear or damage.
(2) Check the outer and inner oil seals for wear
and damage.
Reassembly
To reassemble, follow the reverse of disassembly
sequence, and do the following steps:

1. Front wheel hub

(1) Fill the front wheel hub, especially the roller
holder and oil seal lip groove, with grease.
CAUTION
Take care not to apply grease to the brake drum.

200238

(2) Install the inner race and oil seal retainer of the
wheel hub bearing with an installer (special
tool).
Special tool needed
1.0 to 1.8 ton models 2 to 3.5 ton models Special tool

Installer 64309-123000 91468-00300

204852

(3) Apply sealant to the flange surfaces of the axle

shafts.

6-9
FRONT AXLE AND REDUCTION DIFFERENTIAL

2. Hub bearing preload 1-ton models

1.0 to 1.8 ton models

Tighten the inner nut to obtain the required pre-
load. Tighten the outer nut to the specified torque;
and check the preload. Where the bearings
removed in disassembly are reused, try to produce
a preload in the lower side of the specified range.
Inner nut Outer nut
2 to 3.5 ton models 200468
Tighten the nut to 137 N·m (14 kgf·m) [101 lbf·ft],
and back it off 80º of rotation. Rotate the drum
assembly more than 3 turns, and check the preload. 2, 3-ton models
If the preload meets the specification, put lock ring
and tighten the bolts.
Bolt
1.0 to 1.8 ton 2 to 3.5 ton
models models
0.5 to 4.9 N·m
Preload for hub
(5 to 50 kgf·cm) Lock ring
bearings
[0.4 to 3.6 lbf·ft]
Nut 200239
Force applied to 5.4 to 54 N 4.4 to 44 N
hub in tangential (0.55 to 5.5 kgf) (0.45 to 4.5 kgf)
direction [1.2 to 12 lbf] [0.4 to 3.6 lbf]
196 N·m
Tightening torque
(20 kgf·m) —
for lock nuts
[145 lbf·ft]

NOTE
To check the preload, hook a spring balancer
to the hub bolt, and measure the tangential
force to rotate the wheel.

6-10
 FRONT AXLE AND REDUCTION DIFFERENTIAL

Reduction Differential
Disassembly

1.0 to 2.5 ton models 3 to 3.5 ton models

7
1 20 12

9
10
22
19 21
9 18
8
7 24 13

4 16 12

15 1
17
7
14

3 23
10 11 3
9
7 8
6
5
4
2 207155

Sequence [3-ton models]

1 Mount bracket assembly (right and left) 12 Cover, O-ring
2 Lock washer, Lock pawl, Bolt, Plate 13 Lock nut, Shims
3 Adjusting screw 14 Reduction bevel pinion, Tapered roller
4 Bearing cap, Lock washer, Bolt bearing (inner), Shims
5 Differential case (right), Tapered roller 15 Carrier cover
bearing 16 Tapered roller bearing
6 Differential gear, Thrust washer 17 Driven gear
7 Differential pinion, Thrust washer (not 18 Plate
used in 1-ton models) 19 Drive gear, Ball bearing
8 Differential spider 20 Input flange
9 Differential gear, Thrust washer 21 Ball bearing
10 Differential case (left), Tapered roller 22 Oil seal
bearing 23 Differential carrier
11 Reduction bevel gear

NOTE
For the disassembly sequence for 1, 2-ton
models, see the next page.

6-11
FRONT AXLE AND REDUCTION DIFFERENTIAL

NOTE Sequence [1, 2-ton models]

1) Remove the parts 5 thru 11 as an assembly.
24 Spring pin
8 Differential spider
2) Two-piece differential case is used in 3-ton 7 Differential pinion, thrust washer
models while one-piece differential case is (2-ton models only)
used in 1, 2-ton models. The disassembly 9 Differential gear, thrust washer
sequence for the one-piece case differs
from that for the two-piece case.

Suggestions

NOTE
Before disassembling the differential except
for replacement of the reduction gear set,
measure the gear backlash to aid in obtaining
correct backlash at the time of reassembly.

Unit: mm (in.)
Backlash between reduction 0.15 to 0.25
gear and pinion (0.0059 to 0.0098)
204596

NOTE
Mark across the bearing cap, and carrier on
each side to ensure correct refitting.

204597

6-12
 FRONT AXLE AND REDUCTION DIFFERENTIAL

1. Removing bearing
Use a bearing puller to remove the inner bearing 5.

2. Removing shims
After removing plate 18 and shims 13, make a
record of the total thickness of the shims, and tie
the shims to the plate to prevent missing.

204598

3. Removing carrier cover

To remove carrier cover 15, attach a sling to the
bracket mounting holes, and lift off the cover with
a hoist while tapping it with a plastic hammer at
two places close to the dowel pins.

4. Checking tapered roller bearing

Do not remove the taper roller bearing 14 (inner)
from reduction pinion 14 unless it is defective.

5. Checking oil seal

Do not remove oil seal 22 from carrier cover 15
unless it is defective.

204854A

6-13
FRONT AXLE AND REDUCTION DIFFERENTIAL

Inspection after repair

1. Reduction gear and pinion
Check the gear and pinion for wear, pitting, flak-
ing and chipping. Minor flaws on the tooth sur-
faces can be repaired by grinding with an oil stone
or a sand paper. Check the teeth for contact. If the
gear and/or pinion is badly damaged, replace the
gear and pinion as a set.
2. Differential
3-ton models
(1) Check the differential case 10 for damage.
Check, in particular, the seat formed of each
case for carrying tapered roller bearing inner
race to see whether the seat surface is fretted
or not.
(2) Check the sliding surfaces of thrust washers
and gears for wear and damage.
(3) Check the teeth of the differential pinions and
gears for wear, pitting chipping and galling.
(4) Check the pinions (inside diameter) and pin-
ion shafts (diameter) for wear.
(5) Check the differential gears and axle shaft
splines for free movement (looseness).
206455

A = Assembly standard 1, 2-ton models

B = Repair or service limit Unit: mm (in.)
0.03 to 0.07
Clearance between A
(0.0012 to 0.0028)
pinions and shafts
B 0.35 (0.0138)

B = Repair or service limit Unit: mm (in.)

Free movement (looseness of
differential gear and axle B 0.5 (0.020)
shaft splines)

3. Drive gear and driven gear 206456

Check the gears for wear, pitting, flaking and chip-
ping. Check the teeth for contact. If the gears are
defective, replace them as a set. NOTE
The combination of drive and driven gears
is different from one model of the truck to
another. This combination can be identi-
fied by the marking “A” to “F” punching
on the side face of each gear. When replac-
ing the gears, check the marking to ensure
the proper combination of the gears as
before.

6-14
 FRONT AXLE AND REDUCTION DIFFERENTIAL

Reassembly

16 14 15 13 21 22 23 25
25
20

12

17

18 19

11 24 8 10 4 3 1 2 5 6 7 8 11 24 206457

Sequence
1 Differential case (left) 14 Ball bearing
2 Reduction bevel gear 15 Input flange
3 Bolt 16 Drive gear
4 Differential gear, Thrust washer 17 Ball bearing
5 Differential spider, Differential pinion, 18 Plate
Thrust washer 19 Reduction bevel pinion, Shims, Taper
6 Differential gear, Thrust washer roller bearing
7 Differential case (right)-Bolts, Spacer 20 Driven gear
8 Tapered roller bearing 21 Taper roller bearing
9 Differential carrier 22 Shims
10 Bearing cap 23 Lock nut, O-ring, Cover
11 Adjusting screw 24 Lock plate, Lock pawl
12 Carrier cover 25 Mount bracket assemblies (left and right)
13 Oil seal

6-15
FRONT AXLE AND REDUCTION DIFFERENTIAL

Suggestions

1. Installing reduction gear 1.0 to 1.8 ton 2 to 3.5 ton

To install reduction Bevel Gear 2 to differential models models
case (left) 1, apply LOCTITE No. 271 to the
Tightening torque 118 N·m 216 N·m
threads of bolts 3, and tighten the bolts to the for reduction (12.0 kgf·m) (22.0 kgf·m)
specified torque. gear bolts [87 lbf·ft] [159.1 lbf·ft]

2. Reassembling differential pinions

The thrust washers of the differential gears are
used for adjusting the backlash between the differ-
ential gears and pinions. Measure the backlash
and, if it is in excess of the service limit, replace
the thrust washers.
Backlash between differential gears and pinions
A = Assembly standard
B = Repair or service limit Unit: mm (in.)
1.0 to 1.8 ton 2 to 2.5 ton 3 to 3.5 ton
models models models
0.18 to 0.23 0.19 to 0.25 0.15 to 0.35 204858
A
(0.0071 to 0.0091) (0.0075 to 0.0098) (0.0059 to 0.0138)
B 0.5 (0.020)

3. Installing differential cases [GP/DP30K/35K]

Put the right and left differential cases together
with the marks in alignment. Apply LOCTITE No.
271 to the threads of the bolts, and tighten the
bolts to the specified torque.

123 N·m
Tightening torque for
(12.5 kgf·m)
differential case bolts
[90 lbf·ft]

4. Reassembling differential cases

After positioning the case assembly on the carrier,
install the bearing caps tentatively by making the
cap bolts snug-tight. The caps are to be secured
tight after the bearing preload has been adjusted.

5. Installing bearing caps

Be sure to discriminate between the left and right
caps and to put each cap in place correctly.

6-16
 FRONT AXLE AND REDUCTION DIFFERENTIAL

6. Adjusting bearing preload

Tie a wire on the reduction gear tooth. Hook a
spring balancer to the wire, and pull the balancer
in the tangential direction to check the preload for
the bearing ( the force when the gear starts rotat-
ing).
Adjust the preload by means of the adjusting
screws, right and left.
NOTE
Before measuring the preload, give light taps
of a copper hammer to the back of the reduc-
tion gear while rotating the gear by hand for 204857
running-in.

Preload
1.0 to 1.8 ton 2 to 2.5 ton 3 to 3.5 ton
models models models
1.5 to 2.9 (15 to 30 kgf.cm) [1 to 2 lbf.ft]
13 to 25 N 11 to 22 N 18 to 34N
(1.32 to 2.5 kgf) (1.1 to 2.2 kgf) (1.8 to 3.5 kgf)
[2.9 to 5.5 lbf] as [2.4 to 4.9 lbf] as [4.0 to 7.7 lbf] as
force applied to force applied to force applied to
reduction gear reduction case reduction case
in tangential in tangential in tangential
direction direction direction

7. Removing differential cases

The preload can be checked by doing the steps 1
thru 6 above. Mark across the adjusting screws and
bearing caps, and remove the differential cases
from the carrier.

8. Shimming reduction pinion

Put shims on the reduction pinion in order to adjust
the tooth contact of the reduction bevel gear and
bevel pinion. The standard value of total shim
thickness is 1.8 mm (0.071 in.) but it should be
increased or decreased on the basis of machining
error which is inscribed on the end face of the
reduction bevel pinion.

204859

6-17
FRONT AXLE AND REDUCTION DIFFERENTIAL

[Example]

Where the error is -0.10 mm (-0.004 in.), the total

shim thickness to be 1.9 mm (0.075 in.):

1.8 + 0.1 mm (0.071 + 0.004 in.) = 1.9 mm (0.075 Shims

in.)

The shims are available in four sizes, 0.1 mm

(0.04 in.), 0.2 mm (0.008 in.), 0.5 mm (0.20 in.)
and 1.0 mm (0.039 in.).
206458
9. Installing oil seal
Using an installer (special tool), put oil seal 13 in
carrier cover 21.
Special tool needed
Installer 91268-05400

10. Applying grease to oil seal

Apply grease to the oil seal installed to carrier
cover 12.

Recommended grease: LG2

11. Applying sealant

When putting differential carrier 9 and carrier
cover 12 together, apply sealant to the flange.

206459

12. Adjusting reduction pinion preload

(1) After installing tapered roller bearing 21, mea-
sure difference between the reduction pinion
and tapered roller bearing to determine the
required amount of shim thickness. The stan-
dard value of total shim thickness is 2.3 mm
(0.091 in.)

204862

6-18
 FRONT AXLE AND REDUCTION DIFFERENTIAL

(2) Put the required amount of shims, and tighten

the lock nut 23. The shims are available in five
sizes, 0.05 mm (0.0020 in.), 0.1 mm (0.004
in.), 0.2 mm (0.008 in.), 0.5 mm (0.020 in.)
and 1.0 mm (0.039 in.).

Lock nut tightening torque

294 ± 20
N·m
(30 ± 2)
(kgf·m)
[217 ± 14]
[lbf·ft]

(3) Hook a spring balancer to the bolt hole of the

input flange, and pull the balancer in the tan-
gential direction to check the preload for the
tapered roller bearing (the force when the
flange starts rotating). Adjust the preload by
adding or subtracting the shims.

Force applied to input flange

Gear symbol
in tangential direction
34 to 49 N
A, B, C (3.5 to 5.0 kgf)
[7.7 to 11 lbf] 206460A

(4) After the preload adjustment, stake the upper

part of the lock nut to prevent loosening.

13. Adjusting reduction bevel gear and bevel

pinion tooth contact
(1) Turn the differential carrier upside down.
(2) Install the differential cases (removed in Step
7) to the carrier. Align the marks on the bear-
ing caps and adjust screws on each side.
(3) Adjust the backlash between the reduction
bevel gear pinion by turning the adjusting
screws. Set a dialgage as shown. At the
periphery of the reduction bevel gear, read the
tangential play of the gear.

Unit: mm (in.)
Backlash between reduction 0.15 to 0.25
bevel gear and bevel pinion (0.0059 to 0.0098)

204864

6-19
FRONT AXLE AND REDUCTION DIFFERENTIAL

(4) To adjust the backlash, turn the adjusting

Backlash
screws, right and left, equally in the same
direction so as not to disturb the bearing pre- Increase
load. Decrease

Increase
Decrease

Increase

Backlash
Decrease
206461

(5) Brush a light coating of engineer’s blue on

several reduction bevel gear teeth, on both the
drive and coast sides. Press forward on the
pinion, and rotate back and forth until a con-
tact pattern is noted on both the drive and
coast sides.
NOTE
Refer to Tooth Contact Patterns and
Adjustment on the next page.
204865

14. Tightening bearing caps

Upon checking the tooth contact, tighten the bear-
ing cap bolts to the specified torque, and bent the
lock washer.

1.0 to 1.8 ton 2 to 3.5 ton

models models
Tightening 123 N.m 163 N.m
torque for (12.5 kgf.m) (16.6 kgf.m)
bearing cap bolts [90 lbf.ft] [120 lbf.ft]

6-20
 FRONT AXLE AND REDUCTION DIFFERENTIAL

Adjustment

After the reduction gear and pinion have been

replaced, adjust the tooth contact as follows:
(1) Determine the required amount of shim thick-
ness S on the basis of machining error
inscribed on the end face of the pinion. It is
given by this formula: Shims
S = standard value - (machining error)
[Example]
Where the error is -0.10 mm (-0.004 in.), the
total shim thickness to be 1.9 mm (0.075 in.):
206458
1.8 mm (0.071 in.) - {-0.1 mm (-0.004 in.)}=
1.8 mm (0.071 in.) + 0.1 mm (0.004 in.) =
1.9 mm (0.075 in.)
(2) Put the shims and install the reduction gear
and pinion.
(3) Adjust the tooth contact as shown below.

Tooth Contact Patterns and Adjustment

Tooth contact Adjustment

Extends from toe to

middle portion,
1 covering not less Correct tooth contact
than 50% of tooth
length.

(1) Move gear away from pinion.

Short contact at toe 2 (2) Move pinion toward gear by
2
of tooth increasing shim thickness to
1 secure correct backlash.

1
(1) Move gear toward pinion.
Short contact at heel (2) Move pinion away from gear
3
of tooth by decreasing shim thickness
2 to secure correct backlash.

1
Heavy contact on (1) Move pinion toward gear by
face or top half increasing shim thickness.
4
(addendum) of tooth (2) Move gear away from pinion
2 to secure correct backlash.

Heavy contact on (1) Move pinion away from gear

bottom half (dedendum) 1 by decreasing shim thickness.
5
of tooth (2) Move gear toward pinion to
2 secure correct backlash.

Remark: Repeat the above adjustment until the correct tooth contact is obtained. 203669

6-21
FRONT AXLE AND REDUCTION DIFFERENTIAL

Troubleshooting
Complaints Possible causes Remedies
Gear noise comes out a) Teeth worn excessively or tooth contact out of Readjust or replace.
continuously during adjustment in bevel drive See page 6-21.
normal traveling b) Bearing preloads too much or too little, or Readjust or replace.
bearings worn excessively Preload.
1.5 to 2.9 N·m
(15 to 30 kgf·cm)
[1 to 2 lbf·ft]
See page 6-17.
c) Hub bearings broken Replace.
d) Improper tooth contact between reduction Readjust.
pinion and reduction gear See page 6-21.
Irregular noise comes out a) Bearings associated with bevel drive or Replace.
during normal traveling hub bearings broken
b) Differential side gears having broken teeth, or Replace gears or washers.
thrust washers worn
c) Metal piece in axle housing Clean and replace oil.
d) Bolts securing axle shaft or differential Retighten.
carrier loose Carrier bolts.
60 N·m (6.1 kgf·m)
[44 lbf·ft]
Axle shaft bolts.
86 N·m (8.8kgf·m)
[64 lbf·ft]
Abnormal noise comes a) Fit of differential gears in differential case out Replace worn parts.
out when turning a corner of specification due to wear
b) Teeth broken or differential pinions or side Replace defective parts.
gears, or pinions seized on spider
Differential overheats a) Bearings broken due to too much a preload Replace bearings and
readjust preload.
Preload.
1.5 to 2.9 N·m
(15 to 30 kgf·cm)
[1 to 2 lbf·ft]
b) Backlash between reduction bevel pinion and Readjust tooth contact
reduction bevel gear too small and backlash.
Backlash.
0.15 to 0.25 mm
(0.0059 to 0.0098 in.)

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 FRONT AXLE AND REDUCTION DIFFERENTIAL

Service Data
A = Assembly standard B = Repair or service limit
Unit: mm (in.)
Truck Models GP/DP15K GP/DP20K GP/DP30K
Items GP/DP18K GP/DP25K GP/DP35K
A 0.05 (0.0020)
Face runout of axle shaft flange
B 0.5 (0.020)
Runout of axle shaft (1/2 of dial indicator A 0.5 (0.020) 1.0 (0.039)
reading) B 1.0 (0.039) 2.0 (0.079)
Preload for hub bearing 1
A 0.5 to 4.9 (5 to 50) [0.4 to 3.6]
N·m (kgf·cm)[lbf·ft]
Hub bearing lock nuts
A 196 (20) [145]
(outer) 2
Tightening Axle shaft bolts 3 A 86 (8.8) [64]
torque
Nuts 4 A 215 (21.9) [158]
N·m (kgf·m)
[lbf·ft] Hub blot lock nuts 5 A 59 (6) [43] 181 (18.5) [134]
Axle support bolts 6 A 378 (38.5) [278]
Rim bolts 7 A 86 (8.8) [64] 202 (20.6) [149] —
Wheel nuts 8 A 157 (16) [116] 378 (38.5) [278]
Hubs and wheels

GP/DP15K,18K, GP/DP20K/25K GP/DP30K/35K

5 5 6
6
8

8
1

3
4
4

204990

6-23
FRONT AXLE AND REDUCTION DIFFERENTIAL

A = Assembly standard B = Repair or service limit

Unit: mm (in.)
Truck Models GP/DP15K GP/DP20K GP/DP30K
Items GP/DP18K GP/DP25K GP/DP35K
0.18 to 0.23 0.19 to 0.25 0.15 to 0.35
A
Gear backlash 1 (0.0071 to 0.0091) (0.0075 to 0.0098) (0.0059 to 0.0138)
B 0.5 (0.020)
A 0.02 to 0.07 (0.0008 to 0.0028)
Fit of bevel pinion on spider 2
B 0.35 (0.0138)
1.5 to 2.9 (15 to 30) [1.1 to 2.2]
13 to 25 11 to 22 18 to 34
(1.3 to 2.5) (1.1 to 2.2) (1.8 to 3.5)
Preload for differential case bearing 3 A [2.9 to 5.5] [2.4 to 4.9] [4.0 to 7.7]
N·m (kgf·cm) [lbf·ft] as force applied as force applied as force applied
to reduction gear to differential to differential
in tangential case in tangential case in tangential
direction direction direction
A 0.05 (0.0020), max 0.15 (0.0059), max
Face runout of reduction bevel gear 4
Reduction differential

B 0.05 (0.0020) 0.15 (0.0059)

Backlash between reduction bevel gear and
A 0.15 to 0.25 (0.0059 to 0.0098)
bevel pinion 5
Free movement (looseness) of axle A 0.07 to 0.17 (0.0028 to 0.0067)
shaft splines 6 B 0.5 (0.020)
Reduction bevel gear A
118 (12) [87] 216 (22) [159]
bolts 7
Case bolts 8 A — 123 (12.5) [90]
Tightening
torque 123 ± 5(12.5 ± 0.5) 163 ± 5(16.6 ± 0.5)
Side bearing cap bolts 9 A
N·m (kgf·m) [90 ± 4] [120 ± 4]
[lbf·ft] Carrier bolts 10 A 60 (6.1) [44]
Differential carrier
A 44 (4.5) [33]
cover bolts 11
Mount bolts 12 A 78 (8) [58]
Lock nut 13 A 294 ± 20 (30 ± 2) [217 ± 14]
Input flange bolts 14 A 49 (5) [36]
Preload for reduction bevel pinion taper
A 0.3 to 0.5 (3.5 to 5.0) [0.3 to 0.4]
roller bearing 15, N·m (kgf·cm) [lbf·ft]

6-24
 FRONT AXLE AND REDUCTION DIFFERENTIAL

Unit: mm (in.)
Truck Models GP/DP15K GP/DP20K GP/DP30K
Items GP/DP18K GP/DP25K GP/DP35K

13

12

11

12 15
14
Reduction differential

5
10 3

9
6
1
7 8
4 2

205017A

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